Electrical switching devices, such as circuit breakers, have the task of uncoupling a number of consumers from a power supply network when a specific fault occurs. The classical fault is the occurrence of a short-circuit current and the circuit breakers are conventionally configured to move a switching element in the event of such a short circuit current and thus to decouple the connection between consumers and network.
Electrical switching devices include circuit breakers in the low voltage range. “Low voltage” typically means voltages up to 1000 volts. With an appropriate mechanical design of the switching disconnection lines, these types of switching devices can also be designed for switching voltages of over 1000 volts, such as up to 6.3 kV for example. In particular these types of electrical switching devices such as low voltage circuit breakers are embodied to interrupt current paths in the event of an overcurrent or in the event of a short circuit. They can be designed as single-pole or multi-pole units, especially three-pole units.
These types of electrical switching device are generally known. They have at least one moving contact, at the free end of which a contact piece is disposed. When the switching device is closed this contact piece rests against an opposing contact piece of at least a fixed contact.
The switching device can be switched on and also off manually by way of a handle. The handle is generally embodied as a pivoting handle which is able to be pivoted from an off position to an on position and vice versa. In such cases the handle indicates through its respective position whether the switch is switched on or switched off.
Disposed within the electrical switching device is a switching mechanism by which the movable contact can be moved. Such a switching device also has a tripping mechanism, especially in the form of a tripping shaft, which is able to be bought into active contact with the switching mechanism for tripping the switching device.
The functionality of the electrical switching device can be tested via a test button. The test button in this case is effectively connected to the tripping mechanism. During an actuation of the test button the tripping mechanism can be moved such that it actuates the switching mechanism for separating the at least one movable contact from the at least one fixed contact, in other words for tripping the switching device.
It is not permissible for electrical switching devices, such as circuit breakers, to be able to be switched on when the cover element, which can especially be an accessory cover, is open. This means that if the handle of an electrical switching device is switched on with an opened cover element or accessory cover, either the handle must be blocked before it reaches the switch-on position or the switching device must trip before the switch-on position is reached.